The proposed research, in the broadest terms, in directed toward furthering our understanding of neural systems involved in pain perception and to the development of knowledge that will lead to advances in therapeutic interventions for pain management. Specifically, the proposed research is directed toward understanding the functional and anatomical structural properties of neural systems involved in analgesia induced by electrical stimulation of the lateral hypothalamic area (LH). The primary focus of the proposed research will assess influence of Lh analgesia on formalin-induced pain and examine possible functional relaionships among the LH, periaqueductal gray and ascending nigral pathways in analgesic effects induced by LH stimulation.